Tag Archives: limekiln

Burning sea shells to make quicklime

Burning sea shells to make quicklime once was a great tradition in the North-Atlantic region. In Millstone Park, Hyllestad (W-Norway), we have built two limekilns, reviving old lime burning traditions, involving craftspeople, volunteers and the public. Recently we burnt sea shells to make lime paint and mortar! Read about the experiment in a new poster and web article. Continue reading

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Novel micro-images of lime mortar destruction by frost weathering

Frost is here again and thus weak building materials are at risk, for example traditional lime mortars applied during the last summer season. Over the last few days I was able to observe frost heaving in a lime mortar that has not properly hardened/carbonised due to recent rainy and moist weather. As far as I know, no one has previously documented such ice crystal growth, on a micro-scale. The phenomenon is akin to frost heaving in a soil profile: The force of growing ice whiskers lifting the uppermost parts of the soil. Continue reading

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The limekiln at Hyllestad, Western Norway: Rebuilding a new, “historic” kiln for burning lime

Last year we built a limekiln at Millstone Park in Hyllestad, Western Norway, reported on this website. The kiln was built in a traditional fashion, following Roman and Medieval principles. Experimental archaeology! After one burn, which gave excellent quicklime, the kiln was, unfortunately, badly damaged. Cracks in the masonry! So we had to rebuild the kiln to be able to produce more quicklime! Over the last few months a team of professional, Norwegian masons and local volunteers, 15 people altogether, has undertaken the task: Just a little more work to be done, and soon we’ll have two(!) limekilns, one big and one small – for producing “historic” quicklime in the years to come. For restoring old stone buildings.

Below, you will find a report of the rebuilding, written in Norwegian. Use Google Translate if you are not familiar with the language. The report is written by me and was first published on the website of Millstone Park (kvernsteinsparken.no) a couple of days ago. I work part-time as an Associate Professor for Millstone Park and I am project leader and responsible for building, rebuilding and running the limekiln. Great combination of craft and theory, experimental archaeology! But I’m also involved, privately and through my company, Archaeology & Conservation Services, as a local volunteer. Building and running a historic limekiln is a very big task, many months of work for many people! And though the Norwegian Directorate for Cultural Heritage is a generous sponsor of the project, voluntary work is indispensable. Thank you all! And here’s the report, with many videos and photos: Continue reading

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Taken by the frost! The beauty and destructive force of ice growth on masonry

After 29 years of working with weathering of cultural heritage, I have finally seen it “live”: How the force of ice can destroy plaster on stonework. It is more diverse than I though. A complex and fascinating world of beautiful … Continue reading

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Frostforvitring på kulturminner: Bilder av et fenomen få har dokumentert og formidlet

Mange har meninger om frostforvitring på kulturminner, på stein, murverk, puss og mørtel. Men det er få som har dokumentert fenomenet med bilder. Derfor er det mye synsing om «isens ødeleggende kraft». Her presenteres nye fotos av hva som faktisk kan skje når kalkmørtel blir offer for frost. Det dreier seg bl.a. om islinser som dannes og vokser i eksisterende svakhetsplan og sprenger biter bort. Stedet er den nye, «middelalderske» kalkovnen i Kvernsteinsparken i Hyllestad i Ytre Sogn. Continue reading

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Burning the beaches. Happy New Year from the Faroe Islands!

The Faroe Islands, in the middle of the North Atlantic Ocean. Basalt and other volcanic stone everywhere! Yet, many buildings on the islands were erected by the use of lime mortar, from the Middle Ages on. There is absolutely no limestone on the Faroes. Thus, lime mortar had to be produced by “burning the beaches” – collecting shells from beach deposits, stacking the shells above a fire in a field kiln – and let it happen: Hold the temperature at some 900 degrees centigrade for a couple of days, and out comes quicklime to be mixed with water and beach sand for the mortar. Continue reading

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HOTMIX! Nybrent Hyllestadkalk leskes og testes som restaureringsmørtel på Stavanger domkirke

Endelig i gang med hotmix! Med lesking og testing av nybrent Hyllestadkalk til bruk i mørtel for restaurering. Som mange vil huske, brant Norsk Kvernsteinsenter lokal marmor i en nybygd «middelalderovn» i Hyllestad sist juni, et prosjekt støttet av Riksantikvaren. Planen er å leske og teste brentkalken på flere restaureringsprosjekter i Norge, bl.a. på Selja klosterruiner og Stavanger domkirke. Sidene jeg regelmessig jobber sammen med kollegaer i Stavanger, har vi nå gjort flere tester på domkirken med George Murphy og Bjørn Idland, som er restaureringsmurere ved Arkeologisk Museum (UiS). Det er ikke lett å leske kalk som er brent på tradisjonell måte. For det vil alltid være halvbrente og ubrente biter i slik kalk. Akkurat som i middelalderen. Vi lesket kalken på tre ulike måter, og det var liten tvil: tradisjonell hotmix ga det foreløpig beste resultatet! Continue reading

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“Nidaros: The Portland Cement Cathedral” (Baker Memorial Lecture)

This week I attended the international conference “Rediscovering Traditional Mortars” in Trondheim. The conference was hosted by the Nidaros Cathedral Workshop and it was part of the annual conferences organised by the British Building Limes Forum and its Nordic counterpart.

I was lucky to be invited to keep two lectures, one on the experimental lime burning in Hyllestad earlier this year, and the Baker Memorial Lecture during the gala dinner. A very great honour to keep this traditional lecture for more than 230 delegates! I concentrated the lecture on the use of Portland Cement during the restoration of Nidaros Cathedral from 1869 on. Read on to get a glimpse of all the problems it has caused! Continue reading

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Experimental archaeology: Building a “classic”, intermittent limekiln and burning marble at Millstone Park, Hyllestad, Western Norway

It took us about six months: Building a cylindrical limekiln of the classic Roman/Medieval type with local materials only – stone rubble and clay. In June this year, we built the firing chamber and filled the kiln with 2.5 tons of local marble, covered the kiln with clay on a layer of spruce branches and started burning. Five days and five nights with much of the local community involved! Here’s an extended photo story of the project – the first of its kind in Norway. The quicklime (burnt marble) will be tested at Selja medieval monastery and other restoration projects in Norway. Thanks to all paid and volunteers and support from The ruin restoration programme of the Norwegian Directorate for Cultural Heritage, as well as Hyllestad Municipality! The project was carried out by The Norwegian Millstone Centre/The Museums in Sogn og Fjordane County. Continue reading

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